Rotary selector switches for electronic circuits

ABSTRACT

A multiple position switch in which the moving contact or contacts slide between a pair of parallel sets of fixed contacts, the movement of the moving contact being obtained from the rotation of a knob which is constrained to a plurality of circumferentially fixed positions so that step by step rotation of the knob causes adjacent pairs of fixed contacts to be bridged by the moving contact step by step.

United States Patent Inventor Marcel Henri Deltoer 22 rue Ravon,Bourg-la-Reine, Hauts de Seine, France Appl. No. 879,453 Filed Nov. 24,1969 Patented July 13, 1971 Priority Feb. 3, 1967 France 93626Continuation-impart of application Ser. No. 700,119, Jan. 24, 1968, nowabandoned.

ROTARY SELECTOR SWITCHES FOR ELECTRONIC CIRCUITS 21 Claims, 23 DrawingFigs.

U.S. Cl 200/16 R, 200/11 EA, 200/166 Bl-l, 200/4, 200/18 Int. ClI101h15/00, l-lOlh 9/00 Field of Search 200/4, 14,

16,18, 11.11.11.21, 166 B8, l66 .l.5A,47; 74/3.2,27. 29, 89.15,424.8

[56] References Cited UNITED STATES PATENTS 2,079,124 5/1937 200/47 X2,441,808 5/1948 200/11 (.21) 3,047,683 7/1962 Shlesinger, Jr. 200/4 X3,220,718 11/1965 Wikkerink 74/89.15 3,267,224 8/1966 Vega 200/11 (.11)3,270,148 8/1966 Oxley 200/14 FOREIGN PATENTS 1,141,359 12/1962 Germany200/16 Primary Examiner-J. R. Scott AltorneyStevens, Davis, Miller &Mosher ABSTRACT: A multiple position switch in which the moving contactor contacts slide between a pair of parallel sets of fixed contacts, themovement of the moving contact being obtained from the rotation of aknob which is constrained to a plurality of circumferentially fixedpositions so that step by step rotation of the knob causes adjacentpairs of fixed contacts to be bridged by the moving contact step bystep.

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sum 7 0F 7 I39 a 2 n0 V 2 ATTORNEYS ROTARY SELECTOR SWITCHES FORELECTRONIC CIRCUITS BACKGROUND OF THE INVENTION Switches having multiplemarked positions are already I known. Such switches enable a number ofcircuits or sets of circuits to be successively switched. Generally,these switches are of the rotary type. In order that they can switch anumber of sets of circuits they comprise a stack of associated rotor andstator discs or, with the interposition of bevel gears, a plurality ofpairs of discs, rotor and stator respectively, which occupy variouspositions.

Consequently these types of multiple position rotary switches are bulky,and moreover, the number of circuits on which they can act is limited.Furthermore, they are not particularly suitable for use in thestandardized grids formed with perforations distributed in the form of achecker-work, which are employed to support printed circuits, variouselectronic components, as well as the switches themselves, and wiringassociated therewith.

However, multiple position rotary switches have appreciable advantages.Firstly, their knobs are easy to operate; secondly, the ratchetmechanisms for marking the positions are well known and of simpleconstruction and their operation is familiar to the users of electronicapparatus; and finally, it is difficult to exceed the desired finalposition by quick or violent operation thereof.

The present invention relates to switches having multiple markedpositions, the particular positions being dependent upon the position ofa knob, and which switches are well adapted to standardized perforatedgrids and permit the use of any desired number of circuits.

SUMMARY OF THE INVENTION According to the present invention, there isprovided a multiple position switch comprising a frame, a shaft mountedfor rotational movement on said frame, a knob attached to one end ofsaid shaft for manual rotation of said shaft, a toothed wheel mounted onsaid shaft, at least one pawl, a resilient member connecting said pawlto the frame, the pawl cooperating with the toothed wheel to define aplurality of positions in which the shaft and knob can be rotated intoat least two sets of fixed contact members secured to the frame inparallel relation with one another, a sliding block member arranged toslide between and parallel to the two sets of fixed contact members, anda transmission system connecting said shaft to said sliding block memberwhereby rotational movement of the shaft is converted into translationalmovement of the sliding block.

Thus, on rotation of the knob, the sliding block is translationallymoved, and since it supports along its length an arbitrary number ofmovable contacts, it can effect all the desired switching operationsbetween sets of circuits by travelling along the sets of contacts, eachcontact bridging from one pair of studs to the other.

A single sliding block associated with a plurality of sets of contactsin a row can thus replace all the pairs of stator and rotor discs of themost complex rotary switches and render possible any desired contactarrangements.

The switch, according to the invention, also affords all the advantagesof rotary switches having marked positions, plus the advantage that therotary knob may, if desired, perform more than one revolution withoutthe switch passing the same switching positions.

Various mechanisms may be provided to convert a uniform rotation into analso uniform translational movement such as a screw-and-nut mechanism,which, if desired, may be amplified by a lever, and the rack-and-pinionmechanism.

In addition to those objects discussed above, it above, it is a furtherobject of the invention to provide a multiple position switch whichpermits a distribution of the stationary contacts along the screw with astep as small as the smallest step standardized for printed circuits,namely 1.27 mm. (one-twentieth in.), this displacement by one step ofthe slide being obtained for a unit rotation of the control knob,included between two stable positions established by pawls, reduced to afraction of a revolution as small as, for example, one-twelfth of a turn(30).

The invention also permits, with a small number of parts, greatflexibility in the making of connections between stationary contacts.

In accordance with one characteristic of the invention, with thethreaded shaft or screw having an even number of threads, and inparticular four, shoes cooperating with said screw are made of elasticinsulating material. The shoes surround the screw over half itscircumference and each of them bears a contact bridge, each shoe thushaving the shape of a half-nut.

On the screw having an even number of threads, there corresponds to eachof them a thread which, at all points, is diametrically opposite anotherthread. As in an embodiment of this type the pitch of the threads islarge due to the fact that the screw has a relatively small diameter andthat a small rotation of the screw results in appreciable displacementof the half-nut along same, these threads are substantially inclinedwith respect to the axis of the screw.

Accordingly, a half-nut, even if short, has recessed therein theimprints of these portions of screw threads, two of which, diagonallyopposite near its ends, assure an elastic engagement by pressure of thehalf-nut against the screw into the threads of the latter. Thus, such ahalf-nut engages the screw, is fastened thereto, and cooperates withsame for its longitudinal displacement without the reactions of thethreads on the half-nut during rotation, tending to separate thehalf-nut from the screw.

Therefore, in order to effect the longitudinal sliding of the half-nutalong the screw, there are sufficient means intended simply to preventsaid half-nut from turning, without it being necessary for said means topress the half-nut against the screw.

The use of half-nuts, each of which bears a bridge contact, makes itpossible, by placing them opposite each other and bringing themtogether, with or without stagger, to produce all varieties ofcontact-bearing slides capable of use in a switch of this type.

It is shown that it is thus possible to obtain a switching upon eachangular step of the control knob, or else switching by pairs of circuitsevery two steps of rotation of the control knob.

In accordance with another characteristic feature of the invention, eachcontact bridge borne by a half-nut is an elastic blade which is taperedtowards its ends, which ends are curved at least transversely. Eachblade is fastened to a half-nut and is maintained curved by a capsurrounding the central part of the blade and its resting surface on thehalf-nut, and the cap is maintained on each side by a stud engaged in aradial housing of the half-nut, the width of which housing is greatertowards the axis thereof than towards the outside.

It is thus possible, after having placed the blade on the halfnut, toplace the cap, accentuating the bend of this half-nut and forcing thestuds of the cap into the recesses in the halfnut. In this way, when thehalf-nut is engaged elastically on the screw, the recesses close and thestuds which hold the cap cannot escape from their housing. Furthermore,the blade itself is preferably provided laterally with studs engaging inholding recesses of the studs so that the blade is also fastened by thecap to the half-nut.

The resting surface of the blade against the half-nut is advantageouslya cylindrical portion of the latter while the cap presses the blade onboth sides of said cylindrical supporting surface.

The above-enumerated objects of the present invention, as well as manyof the attendant advantages thereof, will become more readily apparentwhen reference is made to the following description taken in conjunctionwith the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1 through 3 diagrammaticallyillustrate, in elevation, three switches having marked positions;

FIG. 4 illustrates a position-marking device;

FIGS. 5, 6 and 7 are cross sections through movable parts and fixedparts of a switch having a rectilinear translational movement;

FIG. 8 shows, in perspective, a half-nut bearing a contact bridge;

FIG. 9 shows, in perspective, a contact blade;

FIG. 10 shows the cap ofa half-nut;

FIGS. 11 and 12 are top plan views of two types of half-nuts, thethreads of which are a distance apart equal to the length of a linearstep of displacement of a half-nut for an angular step of rotation of acontrol knob;

FIG. 13 is a cross section through an example ofa switch in accordancewith the invention;

FIG. 14 is a side view of the switch shown in FIG. 13.

FIG. 15 shows, in perspective, an element for insertion between the twohousing parts of the switch shown in FIGS. 13 and 14;

FIG. 16 is a section view along the line A-A of FIG. 13;

FIG. 17 is a section view along the line B-B of FIG. 14',

FIG. 18 is a section view along the line C-C of FIG. 17;

FIG. 19 shows, in section, an alternate embodiment of the pawl mechanismproducing the rotation step; and

FIGS. 20 through 23 illustrate different possible embodiments of theslide bearing the bridge contact by means of halfnuts such as shown inFIG. 8.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The switches illustrated inFIGS. 1 through 3 comprise a frame I in the form of a cage, whichsupports the bearing of a rotary shaft shaft 2. A knob 3 is connected tothe end of the shaft 2, and is provided for manual actuation. A toothedwheel 4 (FIG. 4) having triangular teeth is secured to the shaft 2. Apair of pawls 5 supported by the resilient blades 6 engage in the spacesbetween the triangular teeth of the wheel 4. The blades 6 are secured atone of their ends to supports 7 and slide in the supports 7 at the otherof their ends. Thus, the shaft 2 can turn only through fractions of arevolution which are equal to the angular distance between two teeth andit is held in its successive positions.

In the construction illustrated in FIG. 1, the shaft 2 is secured to ascrew 8 having four threads, the screw engaging with a nut 9, which issecured to a sliding block 11 movable between two strips 12 on whichfixed contact members 13 are mounted. The strips 12 are held at theirtwo ends by means of the frame 1 and the cross member 35 so as to beparallel with one another. On rotating the knob 3 through a given anglethe sliding block II moves a given length, which movement is constantthroughout the travel of the sliding block owing to the conversion ofthe rotation into a translational movement by the mechanism comprisingthe screw 8 and the nut 9. The spacing between the triangular teeth onthe wheel 4 is such that each step of the rotation of the knob 3 causesthe sliding block 11 to move step by step between consecutive contacts13.

By reason of the small diameter of the screw 8, the travel correspondingto one revolution of the knob 3 cannot be very great even with amultiple-thread screw. As illustrated in FIG. 2, this travel may beamplified by a lever mechanism. The nut 9 carries a pin 17, on whichthere pivots the lever 16, which is connected to the frame I by a link15 and to the sliding block 11 by a link 18.

Thus, the translational movement of the nut 9 is amplified with asubstantially constant ratio so that the sliding block 11 moves fartherthan the nut 9 for each rotational step of the knob 3. The total travel,and consequently the number of contact members passed over by a point ofthe sliding block for one revolution of the button 3, may thus begreatly amplified.

In the construction illustrated in FIG. 3, a bevel wheel 20 is securedto the shaft 2. The bevel wheel 20 meshes with a bevel pinion 21 securedto a spur tooth pinion 22, which engages in a rack 23 secured to thesliding block 11. By choosing the number of teeth of the gears 20, 21and 22, any desired length of movement of the sliding block 11 maycorrespond to one revolution of the knob 3.

The strips 12 and the sliding block Il may be made of molded insulatingmaterial with incorporated contacts or contacts which are secured to theblock 11. Different arrangements of fixed and movable contacts are shownin FIGS. 5 through 7.

In the construction illustrated in FIG. 5, the sliding block Ilasupports resilient contacts 25 which form a bridge between the studs 26aof the contacts 13a associated with the strips 12a situated on eitherside of the sliding block.

In the case of the construction shown in FIG. 6, the movable contacts 27are C-shaped. The contacts 27 are laterally secured to the sliding block11b by their legs which are fitted into recesses in the same slidingblock. These contacts 27 may thus connect the studs 26h and 26bassociated with the strips 12b and 1212 superimposed on either side ofthe sliding block Ilb. As compared with the construction illustrated inFIG. 5, the possibilities of connection and switching are thus doubled.Cross members of appropriate thickness maintain the strips 12b and 12b,in theappropriate spaced relationship and the contact conductors 1311and 13th,, may be bent over to engage in parallel-aligned holes 29 in aninsulating grid 28, the holes being so located as to form a cross-linedscreen.

FIG. 7 illustrates a construction which is applicable to theconstruction shown in FIG. 1. The contact studs consist of the baredends 30 of the contact blades 13c, and 130 incorporated in the thicknessof the superimposed strips 12c, and 120 The opposite studs 30 areconnected by the blades 31A and 318, each ofwhich is disposed in aninsulating block 32A, 32B comprising an internally screw-threadedportion in engagement with the screw-threaded rod 8. The conductors l3,and where necessary the contact studs 26, may be incorporated in thestrips 12 in the molding stage of the manufacture. They may also befitted into recesses formed in the molding of the strips and of thesliding block and secured in the latter by screws, or bent over tags. Inaddition, the interconnections of the studs may be provided for inadvance in the studs incorporated in the strips 12. For example, asshown in FIG. 2, a number of contact members 39 may be cut out of thesame conductive blade while remaining connected by a common portion 36which is embedded in the material of the strip 12 and comprises a singleconnecting tag 37.

It is also possible to provide over the whole length of the strips 12,single, like contacts 13 and, as shown in FIG. I, to interconnect theirleadout tags by means of a welded conductive bridge 38.

With reference now to FIG. 8, 9 and 10 the slide element is shown at Aand comprises a half-nut 101 of elastic insulating material, a bridgecontact blade 102 (shown in detail in FIG. 9) and a cap 103 (shown indetail in FIG. 10).

The half-nut 101 has, recessed therein, screw threads 104 whichcorrespond to the four threads of a screw V" (See for example FIG. 16.)the diameter at the thread bottom corresponding to that of the half-nut.

The half-nut is limited by two collars 105, each being provided with adovetail notch 106, the widest portion thereof facing the axis of thehalf-nut I01. In addition to the collars 105 (See FIG. 13), the half-nutcomprises a pair of cylindrical supporting surfaces I07 which, for easeof molding, are separated by a groove 108. The width of these surfacescorresponds to that of the base of the dovetail notches 106.

The bridge contact blade 102 is applied against the supporting surfaces107. This blade, whose width decreascs towards the ends, has two studs109 intended to take their positions in the bottom of the notches 106.At the ends, the blade 102 has contact elements 110 which are curvedwith a small radius of curvature in the transverse direction and with alarger radius of curvature in the longitudinal direction.

Each blade 102 is held in place by the cap 103 which, for this purpose,is provided with studs 111 fit into the notches 106. A rectangularcentral portion 112 is interposed between the collars 105' and formswith it a rectangular boss 113 and two supporting edges 114 (See FIG.13) against the blade 102 to curve the latter at the contact with thesurfaces 107.

As the half-nut 101 is made of elastic plastic material, one can, bysqueezing it so as to bring its linear edges together, open the notches106 to insert therein the studs 111 which are locked in position whenthe half-nut resumes its shape.

As shown in FIGS. 11 and 12, two types of half-nuts 101A and 1013 areused. They differ from each other by the fact that in the axialdirection of the half-nut, the threads 104 are shifted apart by thewidth of a linear step p." This linear step p" is the displacement whichthe half-nut undergoes when the screw V turns through anglecorresponding to the step of rotation of its control knob. It will beseen subsequently that, for the embodiment shown, the rotation step isonetwelfth of a revolution while the linear step "P" is l.27 mm. As amatter of fact, in the embodiment shown, the central thread of thehalf-nut 101A passes through the center of said half-nut while in thecase of the half-nut 1018, the central thread is shifted by the step pfrom the center.

In both cases, the half-nut has two thread portions 104a and lb in thecase of the half-nut 101A, and 1040 and 104d in the case of the half-nut1008. The threaded portions form a hook or claw which engage with twodiametrically opposite threads of the screw V" so that the half-nutengages elastically on the latter when pressed into contact with same.The

half-nut is then effectively held in place on the screw by virtue of thegreat obliqueness (due to the length of the pitch of the threads) of theportions 104a, 10411 and 1040,104d of the recessed threads which hookonto the opposite threads of the screw.

In order to facilitate rotation and reduce wear, the screw Vl and thehalf-nuts are made of plastic material of a low coefficient of frictionand which emerge polished from molding, for instance, of the materialknown on the market under the name Delnn."

The screw, equipped with at least one half-nut, is arranged axially inthe housing shown in FIGS. 13 and 14. The housing is formed of twoshells 115 and 116 separated by braces 117, the braces bearing barbsl18.which constitute bosses between stationary contacts. The shells 115and. 116 are substantially similar but reversed with respect to eachother. In the embodiment shown, these shells each bear on six contactsper side, totally 12 contacts. The l2 contacts of one shell are obtainedfrom a single metal sheet suitably cut out and punched. The

cuttings produce, towards the inside of the shells, tongues 119 whichupon molding are incorporated in the moldedmaterial except for theirends 1190 onto which the molded materialis prevented from penetratingdue to the squeezing of each of these portions 119a between two puncheswhich grip same. The punches furthermore provide in the shells, channels120, each of which corresponds to one contact.

The molded material of the shells 115 and 116 is selected, not only forits electrical properties but also for its properties of mechanicalstrength. In particular, the material can be filled with short glassfibers.

The tongues 119 are originally joined together by portions 121 and areextended by small bars 122'which, in the original sheet, are connectedtogether by a longitudinal selvage 123 used for positioning the punchedplate forming the contacts in theshell-shaping mold.

After molding, the parts 123 are eliminated so that the small bars 122become connecting tongues which can be shaped as shown in FIG. 13 insuch a manner as to be electrically separated and so that the distancebetween their planes corresponds to a whole number of steps p"separating, in a printed circuit 125, two consecutive openings 126 insaid circuit. It will be recalled that the standard pitch of theopenings is either 1.27 mm. or 2.54 mm. In a similarly known manner, thecarrying grids" of printed circuits can have staggered holes. That is tosay, the circuits may be formed of alignments of holes with doublepitches of 2.54 mm., spaced apart by a double pitch, the holes of one ofthese alignments being staggered with respect to those of the adjacentalignment by a single pitch.

Between the tongues 119, the portions 121 may be kept, which makes itpossible to form a common line, for instance, for feeding voltage to aplurality of circuits. These portions 121 can also be eliminated asindicated by the dotted lines 127 so as to separate each of the contactsentirely from its neighbor.

I Each shell thus bears towards the inside six pairs of contacts 119aopposite each other, two consecutive pairs being separated by a doublepitch p," while the six corresponding pairs of the lower shell areinterposed between those of the upper shell so that two pairs ofcontacts belonging successively to the upper shell and to the lowershell, and conversely, are separated only by the pitch p.

The barbs 118 (See FIG. 15.) are arranged in such a manner that eachformsa boss which takes its place, respectively, in a space between twoconsecutive ends 119a of the upper shell and of the lower shell. Forthis purpose, the barbs 118 are arranged staggered on both sides of theplane of symmetry of the cross members 117 as shown in FIG. 15. Thesebosses, as will .be made clear below, are intended to facilitate thepassage from one bridge contact of a pair of stationary contacts to thenext one, avoiding any danger of short circuiting between these pairs.

To facilitate the mounting, the two cross members 1 17 which bear thebarbs 118 may be connected by a bow 129 making it possible to positionand hold the two cross members 117 of one and the same unit during theassembly of the housmg.

The bosses formed by the barbs 118 could also be molded integral withthe shells. However, when these shells are molded with materialcontaining an abrasive filler (glass fibers) there is very rapid wear ofthe contact blades 102. Since the cross members 117 to do suffer anymechanical stress, they can be molded of a plastic material of a reducedcoefficient of friction, for instance, ofDclrin."

Each shell finally comprises on its inner face an axial groove 130intended to receive the rectangular boss 113 of a half-nut and, on itsouter face, two grooves 131 in which the assembly rods 132 are housed.

The molded screw V has a head 133 in which there is embedded a fork 134forming the termination of the metal shaft portion 135 to the end ofwhich the operating knob 136 (FIG. 14) is fastened. One of the branchesof the fork forms a spur 137 which, passing through the notch 139provided in the edge of the circular opening of a plate 138, permittingthe passage of the head 133, limits the permissible angle of rotation ofthis screw. This notch may substantially extend over practically acomplete revolution, or else the rotation of the knob 136 can be limitedto halfa revolution or even, as will be seen below, to a smallerfraction such as one-sixth of a revolution. This metal spur 137, movablein the opening of a plate which is also of metal, necessarily limits thepossible rotation of the knob without risk of damage to the lessresistant parts of molded material when the user attempts to force therotation ofthe knob 136 after it has come to the end of its stroke.

In the head 133, between the two branches of the for, there are providedcircular openings 140 each of which contains two balls 141. Between theballs is positioned a compression spring 142.

The plate 138 forms the cover of a molded housing 142.

The section of the cavity 144 which serves to receive the head 133 ofthe screw is of a star-shape 145, in the present case, with 12 rays'.Upon rotation of the screw, the balls 141, pushed by the spring 142,jump from one peripheral hollow of the cavity to the next, imposing uponthe knob and therefore upon the screw a step of rotation correspondingto the angular path between these hollows, namely, in the present case,30. In order for this angular step to correspond to a linear pitch of ahalf-nut equal equal to 1.27 mm., the pitch of the threads of the screwV" is therefore 15.24 mm.

The halls housed in the holes 140 have a small drawback of preventingthe use of an axial passage in the screw V and in the shaft 135. Inorder to remedy this drawback, however, the arrangement shown in FIG. 19can be used.

The screw V is tubular as is the shaft 135, and the head 133 is providedwith axial channels 146. As previously, the

head is rigidly connected with the shaft 135 by a terminal flaring ofthe latter which can be effected by means of attached parts.

In the channels 146, there are arranged the balls 141 and the spring 142which separates them. In this case, the starshaped hollows 147 areprovided in the walls of the housing 143 which are perpendicular to theaxis of the screw. One can thus arrange coaxially to the main knob 136the knob of smaller diameter (not shown), which acts on a shaft axiallytransversing the shaft 135 and the screw V to act on a line adjustmentmember mounted at the end of said screw (coil, potentiometer,capacitor). In this case, the contacts driven by the screw V permitstepwise variations of the magnitudes adjusted by the fine adjustmentmember.

The housing 143, the plate 138 and the pair of shells 115, 116 with thecross members 117 interposed, are assembled, as already indicated, bythe rods 132. These rods constitute preferably (FIG. 14) a pair ofU-shaped straps and are terminated with threaded portions on which thereare screwed the nuts 148 fastening a plate 149 serving as an axial stopto the screw V."

An assembly 101, 102, 103 (that is to say a half-nut bearing a contactbridge) having been engaged on the screw, upon each rotation ofone-twelfth revolution of the latter (FIGS. 13 and 16) the curved ends110 of the blade jump from a stationary contact 119a to the adjacentbarb 118, or conversely, from a surface ofa barb to the following tongueend. As shown in FIG. 13, upon the passing of each barb 118, the curvedend 110 of the blade is spaced from the tongue ends 1190. One thusavoids any risk'of short circuiting between two consecutive tongue endsproduced by the blade coming between said ends.

By using blade ends 110 of a width smaller than the space between twostationary contacts, one could dispense with the use of the bosses whichare formed by the barbs 118. However, in this case, it is necessary toshape the ends 119:: forming fixed contacts in such a manner that theblade ends can rise on the following contact after having dropped" inthe space between them.

Furthermore, as shown, the end 110 is also curved in the longitudinaldirection and the terminal portion of this end cooperates with thebosses 118 while a portion closer to the center of the blade cooperateswith the contacts. The wear due to the rubbing of the end 110 on thecontacts and the bosses is thus distributed over two separate surfaceportions.

Under these conditions, if, as shown in FIG. 20, two identical half-nutsof type 101A or type 1018 are engaged opposite each other, the contactblades 102 are opposite each other, and when the portions 110 of anupper blade touch the two corresponding ends 119a, the portions 110 ofthe lower blade rest against a pair of barbs 118. Thus, upon each stepof rotation of the knob 136, every one-twelfth revolution in the presentcase, the contact is alternately established in the upper shell and inthe lower shell, or vice versa.

If the 12 contacts located on the same side of the switch are connectedtogether, in particular, by preservation of the portions 121, anelectrical connection of two of the tongues 122 belonging to the lowershell and the upper shell, respectively, one can successfully place 12circuits under voltage with a slide composed only of two half-nuts, asshown in FIG. 20.

On the otherhand, if one uses two different half-nuts, for instance, oneof type 101A and one of type 1013, as shown in FIG. 21, the two blades102 are apart one step p." In this case, it is possible, for example,simultaneously, to apply two different voltages to the two circuits of apair of circuits and by rotation of one revolution of the knob, assuringthe placing under voltage successive of six pairs of this type, eachplacing under voltage being separated by a position of rest of thecontrol knob 136.

In the same manner, one can produce a slide bearing six bridge contactsby means of six half-nuts 101 arranged in such a manner that the bladesare opposite each other or a slide (FIG. 23) in which the six blades areshifted three by three by one step. In the first case, one can, uponeach step of rotation of the knob, obtain a group of three connections,the rotation of the knob being limited to four steps, namely, threegroups, and in the second, one can obtain two groups of six connections,the rotation of the knob being adapted to be limited to one step on eachside of an intermediate rest position.

In order for it to be possible to thus place together several half-nutsin order to constitute a complex slide, it is advisable that the axiallength of the half-nuts be practically identical to four steps p so thateach blade 102 can relate to the opposite pairs of ends 119a and one ofthe two adjacent pairs after two steps of rotation.

The useful axial length of screw V"-is therefore equal to one step(pitch) p." of the screw thread (i.e. 12 p.) plus the axial length of ahalf-nut (4 p.), or, in the example considered, 16X 1 .27=20.32 mm.

It is possible to arrange end to end several assemblies consisting of aunit length of screw in two associated shells. Experience shows,however, that it is scarcely possible to place more than three lengthsof screw end to end, and this, furthermore, only under the conditionthat each of them controls only one slide formed of two half-nuts.Beyond this, the manual force necessary for the rotation of the knobbecomes prohibitive.

It will nevertheless be noted that such an embodiment permits theswitching of 12 groups of three circuits, each one after the other.

Although in the embodiments illustrated, the switch in accordance withthe invention has been described and shown as associated with printedcircuits, it may also, in the same manner as ordinary knob selectorswitches, be fastened in the front plate of an apparatus by means ofathreaded sleeve base 152 (FIG. 14) surrounding the shaft 135.

In this case, the tongues 122 can be cut as indicated by the dottedlines and the ends protruding to the outside of the tongue portions 119can be perforated, as indicated at 151, for the soldering of connectingwires connecting the switch to a plurality of any desired circuits (thatis to say, not necessarily printed circuits).

The invention is applicable in all electronic devices employingmicrocircuits and requiring successive switches of circuits, forinstance, for adjustments, measurements, changes of tuning or measuringranges, etc. It is therefore the intent that this invention not belimited to the above, given for exemplary purposes only, but be limitedonly as defined in the appended claims.

What I claim is:

l. A selector switch comprising a rotary knob; a shaft having aplurality of protruding threads and supporting said knob; the knob andshaft having definite angular positions defined by click-stops; at leasta pair of shoes in the form of half-nuts of elastic insulating materialfacing each other and applied against the threads of the shaft; aC-shaped resilient contact blade substantially capping each shoe; a pairof shells facing each other, each enclosing one shoe and provided in thecentral portion with means parallel to the shaft for guiding thecorresponding shoe, and in each lateral portion with a row of stationarycontacts, each cooperating with one end of said blade; and means forfitting together said shells substantially in edge to edge relationshipfor enclosing the shaft, the shoes and the contacts.

2. A switch according to claim 1, characterized by the fact that theC-shaped blade is tapered towards its ends which are curved at leasttransversely, said blade being fastened to the half-nut and held curvedby a cap surrounding its central portion and the resting surface on thehalf-nut, which cap is held on each side by a stud engaged in a radialrecess in the halfnut, the width of which is larger towards the axisthereof then towards the outside.

3. A switch according to claim 2, characterized by the fact that theresting surface of the blade blade is a cylindrical portion of thehalf-nut, and the cap is in contact with the blade only on oppositesides of said resting surface.

4. A switch according to claim 2, characterized by the fact that theblade has lateral studs held in the recesses of the halfnut by the studsof the cap.

5. A switch according to claim 1, characterized by the fact that thepitch of the threads of the threaded shaft is 15.24 mm., while theangular step of the control knob of said shaft is 30.

6. A switch according to claim 1, characterized by the fact that thestationary contacts are tongues embedded in the material of the shellsand protruding towards the inside of the shell, the tongue portionsprotruding outside of the shell providing the electrical connection.

7. A switch according to claim 6, characterized by the fact that theassembly of tongues of one and the same shell is obtained from aperforated single metal blade embedded in the mold upon manufacture, theneedless connections between tongues being eliminated after molding.

8. A switch according to claim 6, characterized by the fact that thestationary contacts located on the same side of a shell are separated bybosses forming, towards the inside of the shell, protrusions which arelarger than the said contacts.

9. A switch according to claim 8, characterized by the fact that thebosses are borne by a pair of small barbs of molded material having alow coefficient of friction with respect to the component metal of theblades; which parts are interposed between the adjacent edges of theshells.

10. A switch according to claim 8, characterized by the fact that theends of the blades are curved in the longitudinal direction and comeinto contact at their terminal portion with the bosses and, via aportion close to their center, with the stationary contacts.

11. A switch according to claim 6, characterized by the fact that thestationary contacts borne by the shells are separated by the same pitch,but are interposed between each other, the distance between twoconsecutive stationary contacts belonging to the two shells being equalto the linear displacement of the half-nut for one step of rotation ofthe control knob.

12. A switch according to claim 11, characterized by the fact that thestationary contacts located on one side of the shells beinginterconnected, the threaded shaft comprises two half-nuts preciselyopposite.

13. A switch according to claim 11, characterized by the fact that thestationary contacts located on the same side of two shells beingseparately interconnected, the screw comprises two opposite half-nuts,the contact blade of which are shifted by one step of lineardisplacement of said half-nuts.

14. A switch according to claim ll, characterized by the fact that aslide formed of several pairs of opposite half-nuts is mounted on thethreaded shaft, the distance between two contact bridges borne by twoadjacent half-nuts being equal to twice the distance between stationarycontacts of one and the same shell.

15. A switch according to claim 11, characterized by the fact that thedistance between two consecutive stationary contacts of one and the sameshell is equal to 2.54 mm., while the axial length of a half-nut isslightly less than 5.08 mm.

16. A switch according to claim 6, characterized by the fact that theshells are assembled by connections between the housing of the head ofthe threaded shaft and a bottom plate which can form the stop for thesaid threaded shaft.

17. A switch according to claim 1, characterized by the fact that thethreaded shaft is rigidly connected with a head comprising at least oneborehole for the housing of two balls with an interposed compressionspring, said head being housed in a housing having star-shapeddepressions which receive the ball portions in elastic protrusion withrespect to said head, the distance between two consecutive depressionsbeing equal to one angular step of rotation of the control knob.

18. A switch according to claim 17, characterized by the fact that thethreaded portion of the shaft and the head thereof are of moldedmaterial of a low coefficient of friction, the flared end of a metalshaft which forms an extension of the threaded portion being embedded inthe molded material of the head.

19. A switch according to claim 18, characterized by the fact that thethreaded shaft, its head and its extension, are tubular are aretransversed by an axial shaft operated by an auxiliary knob.

20. A switch according to claim 18, characterized by the fact that anextension of the flaring of the metal shaft protrudes with respect tothe head and cooperates with the opening ofa metal plate placed againstthe housing containing the head for limiting the rotation of the shaft.

21. A switch according to claim 1, characterized by the fact that thethreadings borne by the two facing half-nuts permit placing the twocorresponding C-blades with an axial spacing equal to one step of lineardisplacement of the half-nuts corresponding to one step of lineardisplacement of the half-nuts corresponding to one step of angularrotation of the control knob.

1. A selector switch comprising a rotary knob; a shaft having aplurality of protruding threads and supporting said knob; the knob andshaft having definite angular positions defined by click-stops; at leasta pair of shoes in the form of half-nuts of elastic insulating materialfacing each other and applied against the threads of the shaft; aC-shaped resilient contact blade substantially capping each shoe; a pairof shells facing each other, each enclosing one shoe and provided in thecentral portion with means parallel to the shaft for guiding thecorresponding shoe, and in each lateral portion with a row of stationarycontacts, each cooperating with one end of said blade; and means forfitting together said shells substantially in edge to edge relationshipfor enclosing the shaft, the shoes and the contacts.
 2. A switchaccording to claim 1, characterized by the fact that the C-shaped bladeis tapered towards its ends which are curved at least transversely, saidblade being fastened to the half-nut and held curved by a capsurrounding its central portion and the resting surface on the half-nut,which cap is held on each side by a stud engaged in a radial recess inthe half-nut, the width of which is larger towards the axis thereof thentowards the outside.
 3. A switch according to claim 2, characterized bythe fact that the resting surface of the blade blade is a cylindricalportion of the half-nut, and the cap is in contact with the blade onlyon opposite sides of said resting surface.
 4. A switch according toclaim 2, characterized by the fact that the blade has lateral studs heldin the recesses of the half-nut by the studs of the cap.
 5. A switchaccording to claim 1, characterized by the fact that the pitch of thethreads of the threaded shaft is 15.24 mm., while the angular step ofthe control knob of said shaft is 30*.
 6. A switch according to claim 1,characterized by the fact that the stationary contacts are tonguesembedded in the material of the shells and protruding towards the insideof the shell, the tongue portions protruding outside of the shellproviding the electrical connection.
 7. A switch according to claim 6,characterized by the fact that the assembly of tongues of one and thesame shell is obtained from a perforated single metal blade embedded inthe mold upon manufacture, the needless connections between tonguesbeing eliminated after molding.
 8. A switch according to claim 6,characterized by the fact that the stationary contacts located on thesame side of a shell are separated by bosses forming, towards the insideof the shell, protrusions which are larger than the said contacts.
 9. Aswitch according to claim 8, characterized by the fact that the bossesare borne by a pair of small barbs of molded material having a lowcoefficient of friction with respect to the component metal of theblades; which parts are interposed between the adjacent edges of theshells.
 10. A switch according to claim 8, characterized by the factthat the ends of the blades are curved in the longitudinal direction andcome into contact at their terminal portion with the bosses and, via aportion close to their center, with the stationary contacts.
 11. Aswitch according to claim 6, characterized by the fact that thestationary contacts borne by the shells are separated by the same pitch,but are interposed between each other, the distance between twoconsecutive stationary contacts belonging to the two shells being equalto the linear displacement of the half-nut for one step of rotation ofthe control knob.
 12. A switch according to claim 11, characterized bythe fact that the stationary contacts located on one side of the shellsbeing interconnected, the threaded shaft comprises two half-nutsprecisely opposite.
 13. A switch according to claim 11, characterized bythe fact that the stationary contacts located on the same side of twoshells being separately interconnected, the screw comprises two oppositehalf-nuts, the contact blade of which are shifted by one step of lineardisplacement of said half-nuts.
 14. A switch according to claim 11,characterized by the fact that a slide formed of several pairs ofopposite half-nuts is mounted on the threaded shaft, the distancebetween two contact bridges borne by two adjacent half-nuts being equalto twice the distance between stationary contacts of one and the sameshell.
 15. A switch according to claim 11, characterized by the factthat the distance between two consecutive stationary contacts of one andthe same shell is equal to 2.54 mm., while the axial length of ahalf-nut is slightly less than 5.08 mm.
 16. A switch according to claim6, characterized by the fact that the shells are assembled byconnections between the housing of the head of the threaded shaft and abottom plate which can form the stop for the said threaded shaft.
 17. Aswitch according to claim 1, characterized by the fact that the threadedshaft is rigidly connected with a head comprising at least one boreholefor the housing of two balls with an interposed compression spring, saidhead being housed in a housing having star-shaped depressions whichreceive the ball portions in elastic protrusion with respect to saidhead, the distance between two consecutive depressions being equal toone angular step of rotation of the control knob.
 18. A switch accordingto claim 17, characterized by the fact that the threaded portion of theshaft and the head thereof are of molded material of a low coefficientof friction, the flared end of a metal shaft which forms an extension ofthe threaded portion being embedded in the molded material of the head.19. A switch according to claim 18, characterized by the fact that thethreaded shaft, its head and its extension, are tubular are aretransversed by an axial shaft operated by an auxiliary knob.
 20. Aswitch according to claim 18, characterized by the fact that anextension of the flaring of the metal shaft protrudes with respect tothe head and cooperates with the opening of a metal plate placed agaInstthe housing containing the head for limiting the rotation of the shaft.21. A switch according to claim 1, characterized by the fact that thethreadings borne by the two facing half-nuts permit placing the twocorresponding C-blades with an axial spacing equal to one step of lineardisplacement of the half-nuts corresponding to one step of lineardisplacement of the half-nuts corresponding to one step of angularrotation of the control knob.